docs: def _timestamp_instants_eq(a, b):
      """Compares two timestamp operands for point-in-time equivalence only."""
      assert isinstance(a, datetime)
      if not isinstance(b, datetime):
          return False
      # datetime's __eq__ can't compare a None offset and a non-None offset. For these equivalence semantics, a None
      # offset (unknown local offset) is treated equivalently to a +00:00.
      if a.tzinfo is None:
          a = a.replace(tzinfo=OffsetTZInfo())
      if b.tzinfo is None:
          b = b.replace(tzinfo=OffsetTZInfo())
      # datetime's __eq__ implementation compares instants; offsets and precision need not be equal.
      return a == b